Devastating wildfires continued to rage across the Los Angeles metropolitan area on Friday, extending mandatory evacuations and school closures across the region. Next week promises little chance of relief; Conditions will remain favorable for both existing fires to grow and modern ones to start as gusty winds persist amid unusually arid conditions.
Officials reported five major fires throughout Los Angeles starting Friday morning. The Palisade Fire in Pacific Palisades and Malibu it consumed more than 20,000 acres, while Eaton’s Fire in Altadena it has grown to over 10,000 acres. Across Los Angeles, at least 10,000 buildings are believed to have been destroyed and 10 people killed.
Favorable fire weather requires arid vegetation, low humidity and sturdy winds. The combination of these ingredients allows fires to spark easily and spread quickly; it was this perilous mix that allowed the Palisades Fire and Eaton Fire to spread beyond the ability of any crew to control them earlier in the week.
Firefighters have already managed to do this start controlling firesaided by out-of-state reinforcements, including water from hydrants replenished and the wind speed decreases. (In addition to the rapid spread of the fires, sturdy seasonal winds in Santa Ana earlier in the week at times prevented firefighting planes from controlling the blazes with water and flame retardant chemicals.) The bad news is that these winds may now cease. the situation will improve soon, and on all other fronts, the situation is unlikely to be favorable to firefighters any time soon.
What will happen next with the weather?
The Storm Prediction CenterThe National Weather Service, which is tasked with issuing fire weather forecasts, says the risk of wildfires in Los Angeles will remain elevated through the coming weekend.
We can expect two more moderate wind events in Santa Ana in the coming days – one early Sunday morning and another likely Tuesday. These gusts can encourage existing fires to spread and ignite additional fires.
The Santa Ana wind event occurs when there is a pressure difference between the Great Basin – a expansive area in Nevada and Utah – and the coastal communities around Los Angeles.
Meteorologists often operate the difference in air pressure between Las Vegas and Los Angeles to predict these winds. The greater pressure difference causes stronger winds to rush towards the coast, fueling existing fires. This is what they predict we will see again in the coming days.
Vegetation across the region will remain extremely arid. It’s now the middle of the rainy season in Southern California, and yet there’s no rain anywhere. Following the third wettest February on record, Los Angeles International Airport has seen just 0.03 inches of rain since the beginning of last summer.
Even though mid-January is the best time for the rainy season in Los Angeles, hopes for significant rainfall over the next week and a half are very slim. NOAA’s Climate Prediction Center announced Thursday that we have officially entered La Niña, an area of colder-than-usual water temperatures in the Pacific Ocean near the equator. Atmospheric changes in response to La Niña could force the jet stream to turn north over the eastern Pacific, sending storms to the west coast of Canada instead of the western United States, depriving states like California of rain.
True to form, the dominant storm track across the Pacific will remain near the Gulf of Alaska through mid-January, providing few opportunities for rain to reach as far south as southern California.
Forecasters expect a faint La Niña to continue through the end of winter, with decent chances of the pattern fading by spring. Unfortunately, this timing may coincide with the beginning of the arid season in Southern California.
That doesn’t mean we may not see opportunities for rain in the coming months. However, little or no rainfall until at least mid-January will keep vegetation across the region extremely arid. The continuing risk of modern fires and additional fire growth will depend on bouts of low humidity and gusty winds, and any additional winds in Santa Ana could prove perilous in the coming weeks.